(1) Field of the Invention
The present invention relates to suspended platforms on which articles conveyed by overhead traveling carriages are mounted, and in particular to suspended platforms which can prevent overturning of articles.
(2) Description of the Related Art
An overhead traveling carriage and suspended platforms for the overhead traveling carriage are arranged such that the overhead traveling carriage can convey an article along a traveling rail and temporarily place the article on the suspended platforms. The article is delivered between the platforms and the overhead traveling carriage. Conventionally proposed platforms include safety members against overturning intended to prevent articles mounted on the platforms from overturning and falling (for example, see Patent Reference: Japanese Unexamined Patent Application Publication No. 2005-206371).
The platforms are provided with side walls having certain heights as safety members against overturning as mentioned above, thereby preventing articles from overturning and falling.
The conventionally proposed suspended platforms have a problem that articles mounted on the platforms overturn and fall when a great quake such as an earthquake occurs. This problem arises because the side walls as the safety members against overturning do not have sufficient heights.
FIGS. 10A to 10C illustrate the problem of the conventional suspended platforms.
In the drawings, the X-axis direction is the transfer direction on the horizontal plane in the case where an overhead traveling carriage mounts an article 500 on suspended platforms 300, and the Y-axis direction is the vertical direction.
As shown in FIG. 10A, the overhead traveling carriage transfers the article 500 in the minus direction of the X-axis and lowers the article 500 in the minus direction of the Y-axis when mounting the article 500 on the platforms 300.
In this case, the time to mount the article 500 can be reduced by reducing the distance (“A” shown in FIG. 10A) by which the article 500 is lowered. With an aim to reduce the distance A, the front walls 320 of the respective platforms 300 are low. The front walls 320 are arranged at the entrance/exit for the article 500 mounted and transferred by the overhead traveling carriage.
As shown in FIG. 10B, the overhead traveling carriage mounts the article 500 on the platforms 300.
As shown in FIG. 10C, the article 500 may overturn and fall when a great quake such as an earthquake occurs. In particular, in the case where the article 500 tilts in the direction of the front wall 320 of either one of the platforms 300, the article 500 overturns toward the front wall 320 and then fall over the low front wall 320.
As described above, the conventional suspended platforms have a problem that articles mounted on the platforms overturn and fall sometimes.